Snow has historically been no stranger in Chicago during the month of April. Official snow records indicate a trace or more of snow has fallen this late in 86 of the past 129 seasons dating back to 1884-85. That’s 67% of the time.

But the amount of snow which fell Monday and the fact it occurred within 3 days of 27°C warmth (on Saturday) and on a day which opened near 20°C is without precedent. Neither has occurred before over the 129 year term of official Chicago snow records.

Monday’s preliminary snow totals through 10 pm came in at 30 mm at O’Hare and 25 mm at Midway.

The 30 mm tally at O’Hare equals the amount of snow which typically falls over the full month of April and was the heaviest official snowfall to occur here so late in a season in 3 decades.